1. Field of the Invention
The present invention relates to an image processing method, apparatus and computer program product, and imaging apparatus, method and computer program product. More specifically, the invention is directed to an image processing apparatus, method and computer program product for calculating a white balance correction coefficient for a color image obtained through imaging using a digital camera or the like. The invention also relates to an imaging apparatus, method and computer program product.
2. Description of the Related Art
Recently, it has been proposed to provide digital cameras with image processing functions, such as a function for correcting white balance of a color image of a subject including a face by making use of a face detection technique.
Imaging environments under which image data are obtained by digital cameras are not necessarily uniform. For example, image data are obtained by imaging performed under various imaging light sources, such as daylight, fluorescence light, tungsten light, and the like. Therefore, if an obtained image is displayed on the screen without any image processing on the image data, a color based on the light source may sometimes be reflected on the image.
Consequently, it is known that a white balance correction is performed to obtain appropriate image data which are not affected by the imaging light source.
In image processing in which a face area is detected from image signals obtained through photographing a subject, and white balance is adjusted for reproducing the face in a favorable color, U.S. Patent Application Publication No. 20060284991 discloses a digital camera that performs image processing for correcting white balance by obtaining a white balance correction value based on those of the image signals determined to be white and a white balance correction value based on image data of the detected face area, and combining the white balance correction values by weighting them according to a face detection accuracy evaluation value to obtain a final white balance correction value.
In the conventional digital camera described in U.S. Patent Application Publication No. 20060284991 that calculates a white balance correction coefficient by setting a weighting factor only by a face detection level, information of contributing factor is insufficient for setting the weighting factor, causing a problem that it can not calculate an appropriate white balance coefficient.
The present invention has been developed in view of the circumstances described above, and it is an object of the present invention to provide an image processing apparatus, method and computer program product capable of calculating an optimum white balance correction coefficient for stable white balance correction. It is a further object of the present invention to provide an imaging apparatus, method and computer program product capable of calculating an optimum white balance correction coefficient for stable white balance correction.